The present invention relates to an art of an image display, and particularly to image display processing which provides a obvious image and good image quality in an information instrument and apparatus such as a PC (personal computer) apparatus that needs a display by means of a progressive scanning system, and particularly to optimum image display processing apparatus and image display processing method which are used in case that a video image signal in a interlace system is handled as a video signal in progressive scanning system.
Presently, for example, in an NTSC (National Television System Committee) system, since an image signal of the interlace system is constructed of repetition scanning lines, movement of a moving picture smoothes, and an obvious image is provided. However, in case of displaying a still picture using an image signal of the interlace system, since images of odd and even fields are alternately displayed, a flicker occurs and a restless image becomes to be frequently displayed.
On the other hand, a high quality TV and an image receiver by means of the progressive scanning system are put to practical use, improvement of quality of an image becomes to be essential.
FIG. 4 is a block diagram of one example of an image display processing circuit (the first prior art) by means of a conventional interlace system (JP-A-168555/1995). Particularly, in the progressive scanning system conducted in the image display processing circuit of the first prior art, in case that a moving picture is detected out of motion of an image, only image signal information of one field is sequentially scanned on a screen at a speed two times as large as an usual case, and an image is displayed. Also, in case of a still picture is detected out of motion of an image, each image signal information of an odd field and an even field is sequentially scanned at a speed two times as large as an usual case, and an image is displayed. Thereby, even for the still picture, occurrence of a line flicker is suppressed.
Conventionally, as this kind of the image display apparatus, there is an apparatus disclosed in JP-A98692/1998 (the second prior art), for example. Particular, the image display apparatus of the second prior art is for converting an image signal of the interlace system into a progressive scanning system, and displaying an image, and in the image display apparatus which is constructed so as to control a switch between field interpolation for outputting a data of a pixel at the same position in one field before onto a line to be interpolated and line interpolation for outputting a data of a pixel included in any one of upper and lower lines adjacent to the line to be interpolated onto the line, based on a motion detection result of motion detection means for conducting level comparison every pixel at the same position between frames different from each other, the following arrangement is adopted. In other words, the motion detection means is arranged so as to conduct level comparison every pixel at the same position in at least a plurality of frames before and behind, and detect whether or not there is motion. In this arrangement, since an interval for the motion detection is longer than conventional one, a phenomenon that the field interpolation and the line interpolation are frequently switched is suppressed, and flicker of a display pixel is reduced. Especially, the motion detection means can be arranged so as to include level comparison means for conducting level comparison every pixel at the same position in one frame before and behind, delay means for delaying a comparison result of this level comparison means by at least one frame, and logic means for outputting a signal for selecting the field interpolation only in case that both an output result of the above-described level comparison means and an output result of the above described delay means are a determination result of xe2x80x9cno motionxe2x80x9d, and for selecting the line interpolation in other cases. Especially, the delay means can be constructed of a field memory and the logic means can be constructed of an AND gate, respectively. Thereby, it is disclosed that, since an interval for determining xe2x80x9cwhether or not there is motionxe2x80x9d is longer than conventional one, even though there are a noise and so forth which are superimposed on an image signal, a determination result of xe2x80x9cwhether or not there is motionxe2x80x9d due to influence by this is not frequently switched, and as a result, occurrence of a task that, as conventional, a luminance level changes due to a difference of an interpolation method of the field interpolation and the line interpolation, and a displayed image flickers and image quality is deteriorated is dissolved.
However, in the image display processing circuit of the conventional interlace system, there are many cases in which, when a still picture (a character information data, for example) is displayed, it cannot be displayed by means of the progressive scanning system without flicker, and as a result, even for a still picture, since only an image of one field is outputted and displayed, there is a task that vertical resolution becomes to be half or a value close thereto.
On the other hand, in case of using an identifying signal for showing motion information representing a still picture/a moving picture, for example coded compressive information (compressive information such as an MPEG), an image display processing apparatus can be considered, in which the identifying signal for showing the motion information is put in header data information of the coded compressive information, and detection means for detecting the identifying signal for showing motion information within this header data information is provided.
However, in this image display processing apparatus, since it becomes to be necessary to insert a specific information data (motion information) and an identifying signal therefor into the coded compressive information, and a new transmitting/receiving device for discriminating the identifying signal becomes to be necessary, there is a task that reconstruction is needed on a current broadcasting infrastructure system.
Therefore, the objective of the present invention is to solve the above-described tasks.
Also, the objective of the present invention is to provide progressive scanning image display processing apparatus and image display processing method in which a still picture having high resolution is easily obtained, and even in progressive scanning display, smoothness of a moving picture image cannot be lost. In other words, the objective of the present invention is to provide progressive scanning image display processing apparatus and image display processing method in which, in case that a video image signal of the interlace system is displayed in progressive scanning, a still picture having high resolution is obtained, and even in progressive scan (double speed scan) display, smoothness of a moving picture image cannot be lost.
The objective of the present invention is accomplished by a progressive scanning image processing display apparatus for converting an image signal of an interlace system into a progressive scanning system and displaying an image, having means for conducting predetermined low band frequency pass processing so as to reduce flicker for a vertical direction signal component of a still picture signal component included in a video image signal, and means for synthesizing a still picture signal component to which the above-described low band frequency pass processing is applied and a moving picture signal component included in the above-described video image signal to generate progressive scanning.
Also, the above-described objective of the present invention is accomplished by a progressive scanning image processing display apparatus for converting an image signal of an interlace system into a progressive scanning system and displaying an image, having an image data memory processing section for generating a graphics image signal which is used for a display screen, a motion detecting circuit section for detecting motion information of a moving picture signal included in a video image signal of an interlace system, which is provided from an external device, a vertical direction low-pass filter for selecting a still picture signal included in the above-described video image signal based on the above-described motion information, and conducting predetermined low band frequency pass processing so as to reduce flicker for a vertical direction signal component of the above-described selected still picture signal and generating a progressive scan signal, a scan line switch for selectively switching the above-described still picture signal output from the above-described vertical direction low-pass filter and a moving picture signal which does not pass through the above-described vertical direction low-pass filter to each other based on the above-described motion information, and outputting it, a progressive scanning synthesis section for synthesizing the above-described still picture signal output from the above-described vertical direction low-pass filter and a moving picture signal that does not pass through the above-described vertical direction low-pass filter, which are output from said scan line switch, to generate a progressive scan signal, and a display section for displaying the above-described synthesized and generated progressive scan signal.
In addition, it is preferable that the above-described motion detecting circuit section has means for making a video signal field screen data generated by using the above-described video image signal to be a unit frame, and conducting difference processing of a current frame that is an up-to-date frame and a frame by one frame before from said current frame and generating one frame interval difference signal, and for conducting difference processing of a frame by one frame before from said current frame and a frame by two frames before from said current frame and generating one frame interval difference signal, and means for detecting the above-described motion information using two of the above-described one frame interval difference signal.
Also, it is preferable that the image processing display apparatus has a field memory for an image which stores the above-described current frame, a field memory for an image which stores a frame by one frame before from the above-described current frame, a field memory for an image which stores a frame by two frames before from the above-described current frame, two low frequency pass filters for conducting predetermined low band frequency pass processing so as to remove a predetermined color signal component from each of the above-described two of one frame interval difference signal, and a synthesis section for synthesizing the above-described motion information using an output from one of the above-described low frequency pass filters and an output from the other of the above-described low frequency pass filters.
Also, it is preferable that each of the above-described two low frequency pass filters includes means for conducting the above-described predetermined low band frequency pass processing so as to remove the above-described predetermined color signal component for a horizontal frequency signal component and a vertical frequency signal component of the above-described one frame interval difference signal which is input to each filter.
Also, it is preferable that the above-described vertical direction low-pass filter has a transversal type finite impulse response filter having a predetermined number of taps.
The above-described objective of the present invention is accomplished by an image display processing method of converting an image signal of an interlace system into a progressive scanning system and displaying an image, having a step including a predetermined low band frequency pass processing step so as to reduce flicker for a vertical direction signal component of a still picture signal component included in a video image signal, and a step of synthesizing a still picture signal component to which the above-described low band frequency pass processing is applied and a moving picture signal component included in the above-described video image signal to generate progressive scanning.
The above-described objective of the present invention is accomplished by an image display processing method of converting an image signal of an interlace system into a progressive scanning system and displaying an image, having an image data memory step of generating a graphics image signal which is used for a display screen, a motion detecting step of detecting motion information of a moving picture signal included in a video image signal of an interlace system, which is provided from an external device, a vertical direction low band frequency pass processing step of selecting a still picture signal included in the above-described video image signal based on the above-described motion information, and conducting predetermined low band frequency pass processing so as to reduce flicker for a vertical direction signal component of the above-described selected still picture signal and generating a progressive scan signal, a scan line switch step of selectively switching the above-described still picture signal output from the above-described vertical direction low band frequency pass processing step and a moving picture signal which does not pass through the above-described vertical direction low band frequency pass processing step to each other based on the above-described motion information, and outputting it, a progressive scanning synthesis step of synthesizing the above-described still picture signal output from the above-described vertical direction low band frequency pass processing step and a moving picture signal which does not pass through the above-described vertical direction low band frequency pass processing step, which are output from the above-described scan line switch step, and generating a progressive scan signal, and a display step of displaying the above-described synthesized and generated progressive scan signal.
Also, it is preferable that the above-described motion detecting step has steps of making a video signal field screen data generated by using the above-described video image signal to be a unit frame, and conducting difference processing of a current frame that is an up-to-date frame and a frame by one frame before from the above-described current frame and generating one frame interval difference signal, and conducting difference processing of a frame by one frame before from the above-described current frame and a frame by two frames before from the above-described current frame and generating one frame interval difference signal, and detecting the above-described motion information using two of the above-described one frame interval difference signal.
Also, it is preferable that the image display processing method has a first memory step for an image which stores the above-described current frame, a second memory step for an image which stores a frame by one frame before from the above-described current frame, a third memory step for an image which stores a frame by two frames before from the above-described current frame, two low band frequency pass processing steps including a predetermined low band frequency pass processing step so as to remove a predetermined color signal component from each of the above-described two of one frame interval difference signal, and a synthesis step of synthesizing the above-described motion information using an output from one of the above-described low band frequency pass processing steps and an output from the other of the above-described low band frequency pass processing steps.
Also, it is preferable that each of the above-described two low band frequency pass processing steps includes the above-described predetermined low band frequency pass processing step so as to remove the above-described predetermined color signal component for a horizontal frequency signal component and a vertical frequency signal component of the above-described one frame interval difference signal which is input to each step.
Also, it is preferable that the above-described vertical direction low band frequency pass processing step has a step of conducting transversal type finite impulse response filter processing which has a predetermined number of taps.